All the ways to grow beautiful dahlia blooms… from tubers, cuttings, or seeds? Which way and why?
Dahlia Tubers
Our #1 choice. Growing dahlias from tubers is the easiest and most reliable way to grow dahlias “true” to variety. This is by far our preferred way to grow dahlias. The benefits:
- easy as pie – they require the least of amount of work, equipment, supplies, and time.
- they are more forgiving than a cutting. When you acquire new tubers, they don’t usually require too much coddling from the time you receive them to the time you can plant them (after your frost free date). Store them in a cool, dark area until you’re ready to plant. Keep an eye on the humidity so that they don’t shrivel up if its too dry. Plant them out when the weather looks favourable.
- if you happen to get a late frost after you’ve planted your tubers where the frost kills off the new growth, as long as the tuber is in good shape it will usually do its best to put up new shoots and carry on growing. While your plant may get set back a couple weeks, it’ll still grow from the tuber and produce some nice blooms for you.
- All growing conditions being equal, our own experience has shown us that dahlia plants grown from tubers consistently produce more viable tubers (tubers with eyes) to harvest in the fall than the same variety grown from cuttings.
- while dahlia tuber “mothers” can and do sometimes succumb to rot after planting out, the young plant can often be saved simply by gently digging up the plant and removing the rotting tuber and then replanting. A young plant that starts to look “wilty” or fails to “take off” is a sign to check the mother tuber for rot.
Dahlia Cuttings
Our less appealing choice for growing dahlias true to variety is via cuttings taken from tubers. We’re sometimes asked if we sell dahlia cuttings and our answer is “no”. Growing dahlias from cuttings is not new… but…interest in growing dahlias from cuttings spiked in Canada in 2023/24 possibly sparked by the desire to provide or acquire “unicorn” varieties that are new, hard to find, or stingy tuber producers. Some will find success in buying and selling dahlia cuttings in Canada and some will not. A cutting taken from a plant can be used as a sort of “insurance” that you don’t lose a plant (ie. varieties whose tubers don’t store well or one that doesn’t produce many or any) or to capture a sport or simply to acquire a new variety. If you’re intent on growing dahlias from cuttings, you’ll still get some nice blooms, but temper your expectations for tubers. The cons of cuttings to be aware of :
- Disease, if present, is propagated faster. Cuttings should only be taken from clean stock that is known to be disease free. If a tuber happens to have a disease and 10 cuttings are taken from that tuber – you’ll achieve 10 diseased plants. There is also risk of spreading disease amongst cuttings taken from “clean stock” if they share a tray with a diseased cutting or if sanitation of tools used to handle and take cuttings is inadequate.
- Growing from cuttings demands additional care and attention and resources. Cuttings require more work, equipment, supplies, time and knowledge than growing from tubers.
- Cuttings are more fragile and are more difficult to ship successfully than tubers. Failures during shipping are more common with cuttings than tubers due to the sensitivity of young plants and the shipping conditions they must endure.
- When you receive a cutting, you may need to pot it up into a larger pot right away to prevent it from getting root bound (if you’re hoping for tubers) unless you intend to grow it on as a pot tuber. You may need to get it under grow lights until your frost free date allows planting out so that it doesn’t get weak and leggy.
- If new growth on a plant grown from a cutting gets killed off by a late frost, there is little chance that the new root system will be able to put up new shoots leaving you with an empty space to fill in your garden.
- Tuber production from cuttings can be hit or miss. Cuttings that become root bound stay root bound. Some varieties may do better with regards to producing tubers than others. The method used to take a cutting may influence tuber production. If your cutting doesn’t produce tubers, you might need to accept that you’ve grown a dahlia like an “annual” and try again next season. As with growing from tubers, some varieties are known to be great tuber producers, while others may only produce a few.
- Splitting clumps of tubers grown from cuttings is not as satisfying or enjoyable as splitting clumps grown from tubers! They are often “hairy” with lots of feeder roots and few viable tubers to harvest. It takes more time to get the job done, and with fewer viable tubers at the end of the day.
- Waste! There is typically a lot of plastic used in the process of generating cuttings. Plastic pots, trays, and shipping containers. While some of it may be recyclable requiring more energy to process and reuse, much of it ends up as trash in landfills.
- The price point… How much are you willing to pay for a cutting? What should the price be? Should it be more or less or the same price as a tuber of the same variety? Would you expect a cutting to cost less because they don’t always produce tubers and often they produce fewer tubers than a plant grown from a tuber? Demand and time will tell…
Seeds
Dahlia seeds do not produce dahlias true to variety. This means that seedling blooms usually look substantially different from their parent dahlias. Growing dahlias from seeds can be fun but is not for everyone because you just never know what you’re going to get! Colour, form, height, growth habit etc can be so wildly different! Genetically dahlias tend to revert to their less desirable traits – single blooms on tall plants. Dahlias grown from seed will usually produce tubers that can be harvested in the fall to store over the winter if you like them well enough. Growing from seed is how new varieties are developed and they take a bit of time (at least 2 years) to come to market and longer to become widely available.
Hopefully you find these musings helpful… may you have a ton of fun growing beautiful dahlias from tubers, cuttings or seeds this year!